The Honoré Mercier Bridge in Quebec, Canada, connects the Montreal borough of LaSalle on the Island of Montreal with the Mohawk reserve of Kahnawake and the suburb of Châteauguay on the south shore of the Saint Lawrence River. It is the most direct southerly route from the island of Montreal toward the US border. It carries Route 138, originally Route 4. It is 1.361 km (0.846 mi) in length and contains four steel trusses on its first section. The height of the bridge varies from 12.44 m (40.8 ft) to 33.38 m (109.5 ft) with the highest sections located over the St. Lawrence Seaway. The bridge is named after former premier of Quebec Honoré Mercier.

The bridge has two lanes of traffic in each direction and a total span of nearly two kilometres. At its highest point, the bridge rises 36 metres above the river. There is a narrow sidewalk on the side headed to Châteauguay that can be crossed by foot or bicycle. The roadway is characterized by numerous repairs.

An estimated 29.5 million vehicles use the bridge every year.

History

Before the bridge was built there was a ferry service.

The Mercier was designed by 11 French-Canadian engineers, who were all graduates of the École Polytechnique de Montréal, and was built by the Dominion Bridge Company Ltd under a government-funded work program. Construction of the bridge began in November 1932 and was completed in the early summer of 1934. It was opened to traffic on June 22, 1934, 10 months ahead of schedule with a toll of 50 cents for an automobile and driver--later reduced to 25 cents. Today there is no toll charged for crossing the bridge.

The original east approach was on Lafleur Avenue, which ran straight into the Gauron Bridge over the Lachine Canal.

The higher section over the Saint Lawrence Seaway was added in the late 1950s. In August 1963, the Quebec Department of Public Works approved the construction of a "second" bridge downstream from the first. This increased the number of lanes from two to four.

Oka Crisis

During the Oka Crisis in July and August 1990, the bridge was closed to all traffic for over a month by Mohawks who supported their brothers from Kanesatake. This closure period led to violent tempers and clashes between Mohawks and people from Châteauguay, and the extension of Autoroute 30 bypassing the Kahnawake reserve.

Mohawks in Support of the Caledonia Group

During the Caledonia land dispute, certain individuals from Kahnawake erected Warrior and Confederacy flags on the steel trusses of the bridge to show their support.

The bridge was closed for a short period, in order to allow several men from the community to climb the structure and secure the flags. To ensure their safety, the Kahnawake Peacekeepers stopped traffic from the Kahnawake side of the bridge, while the Quebec Provincial Police blocked access on the Lasalle side. Several weeks later one of the Warrior flags was removed from the bridge and replaced with a Quebec flag (the red Warrior flag is barely visible in the above picture between the first 'V' section of the truss).

On June 29, 2007, community members of Kahnawake staged a peaceful protest on the bridge, in support of the AFN's National Day of Action. Once again men from the community placed Warrior and Confederacy flags on the structure that spans the St. Lawrence Seaway.

2009 saw the start of a complete rehabilitation of the bridge, the largest ever undertaken in Canada. For the first time since 1934, the deck of the Mercier Bridge will be entirely replaced. The work being undertaken is expected to prolong the bridge's life for another 75 years. The bridge deck will be replaced using prefabricated concrete deck panels. The new deck will consist of more than 1,300 prefabricated concrete panels assembled with steel tension cables. In total, the new deck is an area of 40,684 m2. Numerous lane closures and redirection of traffic is expected to continue until work is completed. The project is being carried out in two phases: the work on Phase A is being handled by Kahnawake's Mohawk Bridge Consortium.

Emergency Closure

On June 14, 2011, due to the extreme deterioration of 10 gusset plates, the 1930's section of the Mercier bridge was closed until September 6 (in time for school restart). Engineers examined each gusset and designed an individual solution of either replacement or reinforcement aimed as a permanent solution, not a patch. Regular inspections found the gussets to be corroded beyond what was expected. Using all known weaknesses of the bridge structure, the engineers undertook a complete recalculation of the load bearing ability of the structure. Once they calculated that and factored in a margin for safety, they decided to close the bridge at 8:04 PM on June 14, 2011.